Chapter 10:

[The obnoxious John Thorpe has been obtruding himself on Catherine Morland
as she is starting to dance with the much more enticing Henry Tilney:]
...This was the last sentence by which he [Thorpe] could weary Catherine's
attention, for he was just then borne off by the resistless pressure of a long
string of passing ladies.

"That gentleman would have put me out of patience, had he stayed with
you half a minute longer. He has no business to withdraw the attention of my
partner from me. We have entered into a contract of mutual agreeableness for
the space of an evening, and all our agreeableness belongs solely to each
other for that time. Nobody can fasten
themselves on the notice of one, without injuring
the rights of the other. I consider a country-dance as an emblem of marriage.
Fidelity and complaisance are the principal duties of both; and those men who
do not choose to dance or marry themselves, have no business with the partners
or wives of their neighbours."

[Catherine Morland:]

"But they are such very different things! --"

[Henry Tilney:]

"-- That you think they cannot be compared together."

[Catherine Morland:]

"To be sure not. People that marry
can never part, but must go and keep
house together. People that dance only stand opposite each other in a long
room for half an hour."

"And such is your definition of matrimony and dancing. Taken in that
light certainly, their resemblance is not striking; but I think I could place
them in such a view. -- You will allow, that in both, man has the advantage of
choice, woman only the power of refusal; that in both, it is an engagement
between man and woman, formed for the advantage of each; and that when once
entered into, they belong exclusively to each other till the moment of its
dissolution; that it is their duty, each to endeavour to give the other no
cause for wishing that he or she had bestowed
themselves elsewhere, and their best interest to
keep their own imaginations from wandering towards the perfections of their
neighbours, or fancying that they should have been better off with anyone
else. You will allow all this?"

[Catherine Morland:]

"Yes, to be sure, as you state it, all this sounds very well; but
still they are so very different. -- I cannot look upon them at all in the same
light, nor think the same duties belong to them."

[Henry Tilney:]

"In one respect, there certainly is a difference. In marriage, the
man is supposed to provide for the support of the woman, the woman to make the
home agreeable to the man; he is to purvey, and she is to smile. But in
dancing, their duties are exactly changed; the agreeableness, the compliance
are expected from him, while she furnishes the fan and the lavender water.
That, I suppose, was the difference of duties which struck you, as
rendering the conditions incapable of comparison."

[Catherine Morland:]

"No, indeed, I never thought of that."

[Henry Tilney:]

"Then I am quite at a loss. One thing, however, I must observe. This
disposition on your side is rather alarming. You totally disallow any
similarity in the obligations; and may I not thence infer that your notions of
the duties of the dancing state are not so strict as your partner might wish?
Have I not reason to fear that if the gentleman who spoke to you just now were
to return, or if any other gentleman were to address you, there would be
nothing to restrain you from conversing with him as long as you chose?"

[Catherine Morland:]

"Mr. Thorpe is such a very particular friend of my brother's, that if
he talks to me, I must talk to him again; but there are hardly three young men
in the room besides him that I have any acquaintance with."